Detection of internal defects in metal fibre composite materials using double-waveguide probe loaded with split-ring resonators

Metal fibre composite materials, for instance turbine blades and other structural components, are extensively employed in not just aerospace but also transportation and other fields. Nevertheless, composite materials are prone to forming defects in the fracture and loss of internal metal fibres, and the defects are expected to impact the performance of structural parts. The current paper puts forward a double-waveguide probe with split-ring resonators for microwave testing, operating at 11.5 GHz for the purpose of detecting fractures and the loss of internal metal fibres in composite materials. The split-ring resonator is capable of remarkably augmenting the electric field intensity in the detection area as compared with the original waveguides; in addition, the double waveguides have the potential to make use of the peak width of the S parameter for the characterization of the defects. The experimental and simulation results verify that the double waveguide probe is capable of precisely detecting internal defects in metal fibre composite materials.